The present invention relates generally to flow control valves and more specifically to such valves which are specifically designed for use in mixing of multiple fluids at predetermined and accurately controlled rates.
There exist a wide variety of applications wherein it is necessary to combine two or more fluids for subsequent use. Examples of but a few of such applications include mixing of paints, solvents and/or thinners; ethylene glycol and water; beverage components; gasoline or other fuels with additives; introduction of an odiferous gas to natural gas being delivered to consumers etc. While presently available means exist currently to properly meter flow rates of two or more fluids whereby a desired mixing ratio may be achieved, these means are not totally acceptable as they generally operate independently of each other and hence may not achieve the desired degree of accuracy under varying inlet and outlet pressures. Further, such arrangements are often relatively complex and hence costly both in terms of initial installation costs as well as in the cost of maintenance and operation thereof.
The present invention, however, overcomes these disadvantages in providing an exceedingly accurate, relatively uncomplicated ratio mixing valve which is capable of maintaining the desired preset mixing ratio without regard to variations in inlet and outlet fluid pressures. Further, the mixing valve of the present invention incorporates an arrangement whereby the flow rate of the mixed fluids may be easily and conveniently varied depending upon demand therefor while continuously maintaining the desired mixing ratio. Alternatively, should it be desirable to adjust the mixing ratio, this may also be easily and conveniently accomplished.
The mixing valve of the present invention combines a variable orifice which operates to meter a first fluid flow in response to changes in the inlet pressure of a second fluid as compared to the pressure of the first fluid measured or sensed downstream of the first variable orifice. This arrangement serves to insure that the fluid pressures of the two fluids immediately prior to being intermixed are maintained substantially equal at all times. A pair of linearly adjustably fixed metering orifices are also provided which operate to control the flow of the respective fluids into a mixing chamber and associated outlet port. Suitable dampening means are also provided to inhibit excessive oscillation of the variable orifice as well which dampening means may be adjustable if desired. A drive arrangement is also incorporated with the adjustably fixed orifices which, because the orifices are linear, is able to insure the desired mixing ratio is maintained while the flow rate of the mixed fluid is increased or decreased.
Additional advantages and features of the present invention will become apparent from the subsequent description and the appended claims taken in conjunction with the accompanying drawings.